This invention relates to liquid dispensers and in particular relates to a lubricant dispenser for the automatic dispensing of a controlled quantity of lubricating liquid to a negative pressure zone of an internal combustion engine.
It is recognized that problems can arise with internal combustion engines where insufficient lubrication is provided to the combustion zones of an engine's cylinders. This can occur for various reasons, an important one being on incorrect fuel to air mixture. If this is too lean, that is, insufficient fuel, this can cause overheating, resulting in adverse consequences. A direct consequence of overheating is the destruction of lubricant within the zone, which in turn leads to attrition problems arising between various components within the zones. Enriching the fuel mixture in part overcomes this problem. However, adverse consequences arise one of which is increased fuel consumption. Accordingly, it is well known that it is important that the correct fuel/air mixture be provided to achieve the correct running of an internal combustion engine.
It follows that in feeding the fuel to the combustion zones, whether it be by way of carburetor or fuel injection devices, it is critical that air leaks be eliminated otherwise the integrity and in particular, the uniformity of the fuel mix cannot be maintained. This problem is compounded as the fuel demands of an engine vary considerably, depending upon the operating conditions thereof, and various adjustments and adjunct means are provided to maintain the fuel/air mixture commensurate to those demands.
A fundamental of an internal combustions engines' operation and in particular, the achieving of the fuel/air mixture discussed above, is the vacuum created by the engine's pistons being displaced. This is utilised to draw in the required air for mixing with the fuel. This vacuum is also utilised in other ways, including operating, in known manner, advance and retard mechanisms to maintain the correct parameters for the engine's operation including the fuel/air mixture. Our dispenser, as with those known to us for achieving the automatic or ongoing lubrication of the upper cylinder zones of an internal combustion engine utilise this vacuum to achieve operation. The relevant prior art known to us comprises U.S. Pat. Nos. 1,325,381 Silver; 1,983,066 Black; 2,204,277 Leigh; 2,614,550 White; 3,509,967 Ballard; 3,664,314 Lankin and 3,834,365 Ussery. As we understand them, all these devices vary considerably from our device with the latter three having quite different requirements and applications. The others vary in numerous ways from our device, both as to structure and operation. Our device, we believe, is more versatile in its application, not only in the range of motor sizes for which it is suitable for use with but also with different fuelling systems, that is, carburetor or fuel injection systems. Further, inlet porting or entry for our device can be provided in several places, the device thus being particularly adaptable as to installation. A particular problem that we believe exists with the known devices, is the extent of "air bleed" they require for operation. This must bear adversely on the fuel/air mixture, in particular the uniformity requirements thereof, as the engine operating conditions vary. As a corollary of this, it would appear that there is considerable variation in the amount of oil being dispensed by these known devices. An object of our invention is to provide an improved liquid dispensing device particularly suitable for lubrication of upper cylinder zones of internal combustion engines which will at least partly overcome the problems of known devices. In particular it has been found that the device has little, if any, affect on the fuel/air mixture and the vacuum characteristics of an engine. The device can be operated over a wide range of vacuums from in the order of one inch and even less of vacuum to over twenty inches of vacuum.